Two very good sites for your preparation in Chemistry:
http://www.youtube.com/watch?v=PT5vbCVLZqU&list=ECD68F9E7D8DA2A705
http://www.docbrown.info/page03/3_34ptable.htm#1a.
http://www.youtube.com/watch?v=PT5vbCVLZqU&list=ECD68F9E7D8DA2A705
http://www.docbrown.info/page03/3_34ptable.htm#1a.
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